Referring to FIG. 1, there is shown a schematic diagram of a folding apparatus according to the prior art. The folding apparatus comprises a pair of fixed knives 12, a pair of cutting rollers 14, a pair of folding rollers 16, and a pair of folding fingers 18.
In general, the web material 11 is cut by the fixed knives 12 and the cutting rollers 14 into a plurality of sheets of web material with the same size. The plurality of sheets of web material are then fed to the pair of folding rollers 16 to form folding lines at predetermined location. The pair of folding fingers 18 are adapted to stack up the plurality of sheets of web material to an interfolded web material 13.
The distance between the pair of folding rollers 16 affects the quality of products greatly. If the folding rollers 16 are too close to each other, collisions may occur during operation, that the web material and the equipment may be damaged. If the folding rollers 16 are too far from each other, the folding line will be too dim, and the folding quality of the product will be greatly affected.
In the prior art, a folding roller 16 is supported only by three bearing units 17 located on both sides and the middle of the folding roller 16. The wider the folding roller is, the greater the deformation and vibration are during operation.